let a =1;
let b =2;


function jia(){
    console.log(a+b);
}
function jien(){
    console.log(a-b);

}
function chen(){
    console.log(a*b);
}
function chu(){
    console.log(a/b);
}
module.exports={
    jia : jia,
    jien :jien,
    chen :chen,
    chu :chu
}